OpenBridge

OpenBridge is an open-source, portable Windows desktop app for browsing, downloading and managing a local content library. It started as a clean-room reimplementation of the discontinued Megascans Bridge workflow and now also indexes the public Poliigon and Poly Haven catalogues as additional providers. It ships with an independent interface and no bundled Quixel, Epic, Poliigon or Poly Haven artwork, fonts, plugins or binaries.

OpenBridge is an independent community project. It is not affiliated with or endorsed by Epic Games, Quixel, Poliigon or Poly Haven. Use it only with assets you are entitled to access.

Download

Download the latest portable ZIP from the repository's Releases page, extract it, and run OpenBridge.exe. No installer or administrator access is required.

The portable package is the only supported distribution. Settings, the encrypted Epic session and the local index live in %APPDATA%\openbridge, so the app folder can be moved or replaced without losing user data.

Highlights

• Three providers with a source switch: Quixel Megascans, Poliigon and Poly Haven. Settings keep a shared library root with a folder per provider.
• Poly Haven provider (1.5.9, unreleased) with the full public CC0 catalogue, local full-text search, category/resolution/map/collection facets, explicit HDRI time-of-day, previews, live HDR/360 HDRI viewing, downloadable map sets and model packages, and a local Library source filter. No account, API key or credits are required.
• Poliigon catalogue browsing (1.5.9, unreleased) with the full public catalogue (7,448 published textures, models and HDRIs), 331-category tree, local full-text search, free/credit badges, facets, previews, watermarked map previews and technical metadata. No Poliigon account or third-party search key is required for browsing.
• Poliigon account (1.5.9, unreleased) with browser sign-in, DPAPI-encrypted token storage, plan and credit balance, owned-asset sync and owned badges. Password sign-in is hidden because Poliigon currently rejects addon password login.
• Poliigon downloads (1.5.9, unreleased) with resolution/map/LOD/renderer options, resumable file transfers, pause/resume/cancel, generated MaterialX files and the exact folder layout the official Poliigon Blender addon reads. Free and owned assets require a Poliigon sign-in.
• Unified local library (1.5.9, unreleased) with All/Megascans/Poliigon/Poly Haven source filters, local provider previews, downloaded-resolution/map/LOD facts, search, categories, health checks and automatic rescan after each download. Library means only files already on disk — available offline and independent of catalogue subscriptions. The topbar Check library action only audits acquired assets against that local disk state and never downloads anything.
• Combined Discover (1.5.9, unreleased) with an All source scope as the default view. It merges Megascans, Poliigon and Poly Haven results into one grid/list, searches all catalogues together, and maps all provider trees into one content taxonomy (3D Assets, 3D Plants, Surfaces, HDRIs, Atlases, Decals, Brushes, Imperfections, Displacements) with cross-source subtopics such as Architecture, Furniture, Food & Drink, Rocks & Terrain, Wood & Flooring and Houseplants. Provider category and type filters are applied behind each unified node, and the view combines all facet sets, counts, size/state/downloaded filters, saved searches, recent searches and recently viewed assets, Megascans packs, scroll restoration, bulk selection and download queues. Each provider remains available as a focused single-source view.
• Poliigon parity tools (1.5.9, unreleased) with ID/URL/description search, relevance sorting, recent searches, local favorites, downloaded badges and filters, related assets, clickable categories/tags, list/compare view, expandable render previews, genuine 1K map previews for textures and 3D models with full-screen zoom upgrading to the highest available map resolution, HDRI map previews with both Tone-mapped JPG and HDR (EXR) entries, an interactive drag-to-look 360° panorama for both entries (mouse look, wheel FOV, P toggles flat/360), and a full-screen linear HDR exposure slider that loads the highest published HDR tier (−10 to +10 EV, live GPU tone mapping from the decoded EXR), a Megascans-style Relative size panel and technical grid, bulk selection/download and per-type remembered download options.
• Catalogue browsing for the legacy Megascans catalogue, including nested categories, filters, saved searches, related assets and a command palette.
• Browsing productivity with local categories/favorites, recorded-pack exploration, recent searches/assets, drawer Back/Next, preserved scroll position and adjustable thumbnail sizes.
• Workspace improvements (1.5.9, unreleased) with scoped Catalogue/Library search, a shared filter workbench, a docked wide-screen inspector and always-visible download controls. Narrow windows retain an overlay drawer.
• Filter audit (1.5.9, unreleased) with type-aware filter and sort sets for every provider and asset type, canonical Poliigon map facets, physical-size filters/sorts for Poliigon and Poly Haven, numeric resolution and map ordering, humanised facet labels, and a docked filter panel whose group rail and values scroll independently so results stay visible.
• Visual inspection with expanded render/map previews, zoom/pan and offline JPG/PNG/WebP maps.
• Epic sign-in via OAuth. Tokens are encrypted with Windows DPAPI (safeStorage); passwords are never stored.
• Download engine with per-type presets, map/LOD/variation selection, resumable transfers, size verification, pause/resume, persistent queues and the original library folder layout.
• Transfer awareness (1.5, unreleased) with sidebar progress, a mini queue, session totals, volume free space and completion history saved independently of the queue. Library-size figures are cached health measurements, not a live folder scan.
• Local library index backed by SQLite/WAL and FTS5, with incremental scans, server-side counts, virtualized grids, health reports and bulk tools.
• Asset intelligence with download plans, per-map technical details, LOD triangle counts, physical dimensions, readiness badges and plant billboard previews.
• Relative size (1.5, unreleased) shows a front-view bounding box next to a 1.78 m human on the Overview page, using one shared scale. Assets without complete dimensions are explicitly marked.
• Local-first metadata pack that optionally adds remote catalogue readiness, semantic, pack and freshness metadata without bundling the raw catalogue.
• Portable updates from GitHub releases with size and SHA-256 verification.
• Legacy interoperability through the local HTTP API, discovery service and Mixer sockets.

Requirements

• Windows 10 or Windows 11, x64
• An Epic account with access to the assets you download
• Node.js 24+ and npm for development only

Getting started

npm ci
npm run typecheck
npm run start

For a portable build:

npm run dist:portable

Outputs are written under dist/. See docs/BUILD.md for packaging, release and metadata-pack details.

Configuration

Copy config.local.example.json to config.local.json and fill in the legacy service values needed for catalogue and authentication. The local file is git-ignored and must never be committed. Equivalent environment overrides are documented in docs/BUILD.md.

The release and update URLs are derived from the build repository, so the source tree does not hard-code an account or repository owner. Set OPENBRIDGE_REPOSITORY=owner/repo only when building outside a Git checkout.

Project automation

• .github/workflows/quality.yml runs type checking and the public-repository hygiene check on pushes and pull requests.
• .github/workflows/release.yml builds and publishes the portable ZIP and latest.json when a v* tag is pushed.
• npm run check:public scans tracked text files for credentials, personal paths, account details and machine-specific data.

The optional catalogue metadata pack is generated separately and uploaded as catalog-metadata.json.gz on the release. It is never bundled into the app ZIP.

Privacy

OpenBridge has no telemetry or analytics. Credentials, catalogue metadata and the local index stay on the user's machine. The public repository is kept free of real account names, email addresses, local file paths, machine identifiers and secrets.

Please report security issues privately as described in SECURITY.md.

Limitations

• Windows x64 portable builds only.
• No installer, Linux or macOS build.
• Poliigon browsing, account sign-in, downloads and local-library indexing are available in the current unreleased build. Free assets still require sign-in. In-app purchases are intentionally not implemented; OpenBridge assumes you already have access through your subscription or owned assets. See docs/POLIIGON.md.
• DCC export/plugin installation, Fab browsing and the Three.js preview are not implemented.
• Automatic updates require a published release manifest.
• Some catalogue fields are sparse in the legacy API; the UI hides unavailable data rather than showing placeholders.

Documentation

• Build and packaging
• Testing
• Networking policy and verification
• Roadmap
• Local API and export protocol
• Reverse-engineering notes
• Poliigon research and integration plan
• Poly Haven provider notes
• Research toolchain
• Contributing
• Security policy

License

MIT. See LICENSE.

Country flag artwork in src/renderer/flags comes from flag-icons and is MIT licensed. See src/renderer/flags/LICENSE.